Je. Mcpherson et Sj. Taylor, DISTINGUISHING NYMPHAL INSTARS OF MESOVELIA-MULSANTI (HETEROPTERA, MESOVELIIDAE), Great Lakes entomologist, 26(3), 1993, pp. 233-236
The five nymphal instars of Mesovelia mulsanti can be separated by the
number of rows of setae on the second abdominal tergum. Fifth instars
can be separated from younger instars and from each other by the degr
ee of development of the external genitalia.